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Do I need to run dual wastegates?

I have been doing LOTS of research for my build and was told that I need to run dual wastegates to get the best results... I was told that running two wastegates will cut down on back pressure, allowing my turbo to spool quicker.

I am going to run a GT4088 Garrett turbo pushing 20psi+... The manifold I found to accomodate the dual wastegates is LoveFabs Excalibur manifold... Someone please clear this up for me because my best friend told me that I would be fine with a single wastegate with a stiffer spring.

On a 40 series turbo or larger, that's definitely a good recommendation. Two Tial V44 Wastegates would be superb for you. The thing you have to remember with the 40 series turbos, is that generally they are a divided exhaust housing. This means that two of your exhaust ports are going to empty into one side of the turbo, the other two into the other side. This is where dual wastegates comes in. Just make sure the manifold is divided if the turbo is.

it completely depends on your setup and what wastegates. Im only running a single and running over 30psi with no problems whatsoever. Turbonetics single 55mm works great. twin 44 work good as well. My only "personal" opinion about running two is the same with running two anything; you have double the chance of something going wrong. Simple is better sometimes so running one can be easier for tuning and diagnostic but its just my opinion. Ive seen great results with both.

Thanks guys for the responses... I think I will look into the dual Tial wastegates a little more... I'm sure I'll have more ?'s soon so I'll keep an eye out for both of your responses to those as well... Thanks again

If you run high boost you can get away with only one WG because less air flow is going through it, now if you have low boost settings and your spooling the shit out of it, you need a larger one than a 40mm

I have been doing LOTS of research for my build and was told that I need to run dual wastegates to get the best results... I was told that running two wastegates will cut down on back pressure, allowing my turbo to spool quicker.

Pressure in the turbo manifold is what spools the turbo. Lowering that pressure will slow your spool.

Originally Posted by BoostedH22CB7

I am going to run a GT4088 Garrett turbo pushing 20psi+... The manifold I found to accomodate the dual wastegates is LoveFabs Excalibur manifold... Someone please clear this up for me because my best friend told me that I would be fine with a single wastegate with a stiffer spring.

Big (or multiple) wastegates are needed to control low boost on big turbos. The higher the boost the more exhaust energy goes to spin the turbo, and the less goes out the wastegate *so the smaller the wastegate needed*.

A lot of the wastegate sizing is a matter of intelligent design. You can look at the manifold and get a pretty good idea. I've tuned GT40 on twin 44mm wastegate FR manifolds for K20A2 in EP3; due to the horrible angles the wastegates exit at the exhaust has a hard time changing direction to flow out of them, and with 11 psi springs boost creeps to 15+ psi. Another car has a single 44mm gate w/ 11 psi spring for it's GT40, but the wastegate exit is angled downward from the collector so that it is easy to bypass the turbine, and thus the car maintains 11 psi wastegate flat as a strap. With the boost turned up, both manifolds/wastegate setups w/ GT40s do a great job of controlling boost.